Page 1: Internal Combustion Engines in Marine Propulsion

Overview

• Internal combustion engines (ICE) play a vital role in marine propulsion.

• They convert fuel combustion (diesel, gasoline, LNG, or dual fuels) into mechanical energy to power vessels.

Types of Marine ICE

1. Two-Stroke Engines

• Working Principle: Completes intake, compression, power, and exhaust in 2 strokes (1 crankshaft revolution) using ports.

  • Stroke 1: Piston compresses fuel-air mixture.

  • Stroke 2: Combustion pushes piston down; fresh mixture enters, and exhaust exits.

• Advantages: High power output, simpler design.

• Disadvantages: Poor fuel efficiency, higher emissions, increased wear.

• Applications: Large ships, oil tankers, cargo vessels.

2. Four-Stroke Engines

• Working Principle: Completes its cycle in 4 strokes (2 crankshaft revolutions), using valves for fuel-air intake and exhaust.

  • Stroke 1: Intake valve opens to draw in mixture.

  • Stroke 2: Piston compresses mixture.

  • Stroke 3: Combustion ignited by spark plug forces piston down.

  • Stroke 4: Exhaust valve opens, expelling gases.

• Advantages: More fuel-efficient, smoother operation.

• Disadvantages: More complex, higher maintenance costs.

• Applications: Smaller ships, passenger ferries.

Page 2: Key Components of Marine ICE

Key Components and Systems

• Components work together to maintain efficient combustion and power generation.

2. Engine Components

• Engine Block and Cylinders: Structural foundation housing main components. Cylinders vary in number (6-12).

• Pistons: Convert combustion energy to mechanical power.

• Crankshaft: Converts linear motion of pistons to rotational motion, made from forged steel.

• Cylinder Head and Valves: House key components; control air-fuel mixture intake and exhaust gas expulsion.

• Fuel System: Ensures precise fuel delivery and combustion efficiency.

• Turbocharger and Intercooler: Improve air intake for better combustion power.

• Exhaust System: Manages emission gases and may include scrubber systems for emissions reduction.

Page 3: Components Continued

A. Engine Block and Cylinders

• Engine Block: Supports engine components, typically made of cast iron or aluminum alloys.

• Cylinders: Number depends on engine size; arrangement affects power output.

B. Pistons

• Function: Move inside cylinders using combustion force.

• Piston Rings: Seal around the piston preventing gas escape.

Page 4: Key Components Continued

C. Crankshaft

• Converts piston motion into rotational motion; made from durable forged steel.

• Supported by bearings to minimize friction.

D. Cylinder Head and Valves

• Contains intake and exhaust valves; regulated by the crankshaft.

E. Fuel System

• Fuel Injection System: Ensures efficient combustion; includes fuel pump and common rail systems.

F. Turbocharger and Intercooler

• Turbocharger: Enhances air intake for combustion.

• Intercooler: Cools intake air to improve combustion efficiency.

G. Exhaust System

• Manages waste gases, includes systems for emission reduction compliance.

Page 5: Cooling and Lubrication Systems

H. Cooling System

• Prevents overheating using freshwater or seawater cooling methods.

I. Lubrication System

• Circulates oil to reduce friction and wear; includes oil pump and filters.

Page 6: Diesel Cycle (Compression Ignition)

Stages of the Diesel Cycle

1. Intake: Air drawn into the cylinder via the open intake valve.

2. Compression: Air compressed by piston movement, leading to high thermal efficiency.

3. Fuel Injection: Fuel injected under high pressure ignites spontaneously.

4. Power: Expanding gases push the piston down, transferring energy.

5. Exhaust: Exhaust valve opens, expelling burnt gases.

Page 7: Performance Metrics

A. Specific Fuel Consumption (SFC)

• Measures efficiency; typical range for marine diesel engines is 160-220 g/kWh.

B. Power Metrics

• Indicated Power (IP): Power produced during combustion.

• Brake Power (BP): Usable power measured at the crankshaft.

C. Compression Ratio

• Critical for fuel efficiency; higher ratios lead to better economy.

Page 8: Maintenance Practices

A. Preventive Maintenance

1. Oil and Filter Changes: Regular changes help maintain engine health.

2. Fuel System Inspection: Inspect injectors and ensure fuel quality.

3. Turbocharger Checks: Monitor bearings and blade conditions.

Page 9: Weekly Maintenance Procedures

A. Engine Oil and Lubrication Systems

1. Change oil as per schedule; check oil pressure during operation.

2. Inspect fuel filters and injectors for performance issues.

B. Cooling System Checks

1. Verify coolant levels and clean seawater strainers.

Page 10: Monthly and Annual Maintenance

A. Monthly Maintenance

1. Engine Compression Check: Confirm sealing and performance metrics.

B. Annual Maintenance

1. Complete Engine Overhaul: Inspect and replace worn components.

Page 11: Troubleshooting and Diagnostics

Common Engine Problems

1. Won't Start: Check battery and fuel system.

2. Excessive Smoke: Inspect combustion efficiency and fuel quality.

Page 12: Electrical System Faults

Types of Electrical Faults

• Short Circuits and Open Circuits detailed.

• Testing Tools: Multimeters and oscilloscopes for diagnostics.

Page 13: Maintenance Documentation

Importance of Documentation

• Ensures compliance and reliability; includes logs and reports.

Page 14: Safety Precautions

Personal Protective Equipment (PPE)

• Required for all maintenance activities to ensure safety.

Page 15: Handling Fuel and Chemicals

Fuel Handling Practices

• Use approved containers; ensure proper storage protocols.

Page 16: Inspection Practices

Routine Inspections

• Regular checks for wear and cleaning processes.

Page 17: Fresh Water Generators

Working Principle

• Vacuum distillation process ensures efficient freshwater production.

Page 18: Types of Fresh Water Generators

Distillation Methods

1. Plate Type: Advantages in heat exchange and efficiency.

2. Tube Type: Similar principles with different structural design.

Page 19: Starting and Stopping Procedures

Fresh Water Generator Operations

• Steps for startup and shut down to ensure safety and effectiveness.

Page 20: Faults in Fresh Water Generators

Common Issues

• Loss of vacuum, saltwater carry-over, scale formation.

Page 21: Scale Formation Prevention

Chemical Treatment

• Continuous treatment with polysulphate compounds for maintenance.

Page 22: Domestic Water Systems

Distribution and Heating

• Systems for distributing and heating freshwater throughout the vessel.

Page 23: Drinking Water Systems

Treatment and Distribution

• Process for ensuring potable water and mineral addition steps.

Page 24: Emergency and Cross-Connections

• Protocols for emergency freshwater use and maintenance basics.

Page 25: Setting Up Hydrophore System

Commissioning Procedures

• Steps for starting the system and ensuring proper pressure levels.

Page 26: Procedures for Maintaining Fresh Water Systems

Hydrophore and Domestic Water Operations

• Operational guidelines for efficient water distribution.

Page 27: General Safety Maintenance

Regular inspection recommendations for various components.